Articulated connector

ABSTRACT

A connector for the terminal ends of the coil springs such as are employed in a coil spring filter, includes a pair of plugs each proportioned for reception within the said terminal ends, and means interconnecting the plugs for universal relative angular movement and to withstand the spring tension. The adjacent ends of the plugs are formed with relatively opposed shoulders which are spaced apart to define between them a space for reception of inwardly directed terminal ends of the wire filament or filaments forming the coil spring or springs. The abutting engagement between the similarly directed ends with the said shoulders prevents removal of the plugs from the springs. In a preferred embodiment, the universal interconnection between the plugs is defined by forming the plugs with relatively aligned bores through which is loosely disposed a rigid pin having sufficient clearance with the bores to permit limited angular movement of the plugs in an axial plane of the pin. The ends of the pins are enlarged to retain the plugs thereon and the plugs are relatively freely rotatable to release any torsional forces in the spring ends which might tend to laterally displace them by rolling motion on the filter drum or associated rollers.

United States Patent Primary ExaminerSamih N. Zaharna Assistant Examiner-T. A. Granger AttorneyRichard E. Babcock, Jr.

Schlegel 1 Oct. 31, 1972 [54] 'ARTICULATED CONNECTOR [72] lnventorz William L. Schlegel, Stanhope, NJ. [57] ABSTRACT [73] Assign: vKomlimfs'mdermn Engineering A connector for the terminal ends of the coil springs I Corporation Peapack N J such as are employed In a coil spring filter, includes a pair of plugs each proportioned for receptionwithin [22] Filed: Nov. 1,1971 the said terminal ends, and means interconnecting the plugs for universal relative angular movement and to I [211 App! l94168 withstand the spring tension. The adjacent ends of the plugs are formed with relatively opposed shoulders [52] U.S.Cl ..210/401, 24/31 which are spaced apart to define between them a [51] Int. Cl. ".8011! 33/14 Space for reception of inwardly directed terminal ends [58] Field oi Search....ll4l235; 24/31 R, 31 B, 31 C; of the wire filament or filaments forming the coil 210/401, 336; 235/397 spring or springs. The abutting engagement between the similarly directed ends withthe said shoulders [5 R f -gn e Cited prevents removal of the plugs from the springs. In a preferred embodiment, the universal interconnection UNITED STATES PATENTS between the plugs is defined by forming the plugs with 1 271 014 7/1918 Bower ..24/31c 'i' aligned hmugh which is mosely l371513 3 H921 Nickerson 24/31 C disposed a rigid pin having sufiicient clearance with 2652927 9/1953 Komline [401 the bores to permit limited angular movement of the l976 10/1971 Hale I' F I plugs in an axial plane of the pin. The ends of the pins 24505l9 10/1948 g l 24/31 are enlarged to retain the plugs thereon and the plugs 1683697 Rankin "24/31 are relatively freely rotatable to release any torsional forces in the spring ends which might tend to laterally displace them by rolling motion on the filter drum or associated rollers.

2 Claims, 3 Drawing Figures This invention relates to an improved articulated connector for coil springs and is particularly adapted for use in interconnecting the ends of closely wound coil springs to form endless spring elements for use as the components of filter media in rotary drum filters as exemplified in the prior U.S. Pat. Nos. 2,652,927; 2,652,928 and 2,699,260 of T. R. Komline.

In rotary drum filters of thetype here involved, the filter media is of composite construction consisting of a plurality of generally parallel and contiguous endless coil spring loops of stainless steel moving through an endless circuit around a drum and supplemental rollers of substantially smaller diameter than the drum.

I The spring portions in moving through said endless circuit, pass repeatedly around the drum and each of such rollers. Therefore, each spring loop will include materials and minimum risk of failure of the connector itself.

In accordance with the invention, the connector employs a pair of plug members interconnected for relative universal angular movement. Preferably the plugs have generally aligned bores therethrough and are interconnected by a rectilinear pin extending through the bores with sufficient clearance to permit limited relative angular movement of the plugs in all axial planes of the pin, the pin having means at its opposite ends for retaining the plugs thereon while permitting said limited relative angular movement as well as .relative normally straight runs between rollers, and between the rollers and the drum, and curved portions passing around the rollers and the drum, and conforming as closely as possible to the curvature of each.

In the past, the ends of the spring coils have been coupled together by rigid connectors, generally in the form of externally threaded plugs threaded into the interconnected end portions of thesprings.

Breakage of a single spring of the composite filter media, needless to say, will result in the admission of unfiltered liquid or slurry to the interior of the drum, with resulting contamination of the filtrate.

Manifestly, it is highly desirable to extend the life of the filter media and the individual spring coil section or loops comprising the same, for as great a time as possible.

With this in mind, it has been observed by the undersigned inventor that where the adjoining spring ends are connected by conventional rigid plug type connectors such as heretofore employed, any breakage or failure of a spring which 'occurs, will invariably be closely adjacent to one of the said connectors. It is believed that such'failure arises from the fact that when the spring attempts to conform to the curvature of a roller in passing therearound, the rigid connector plug interconnecting adjacent portions of the spring is unable to assume a corresponding curvature. Therefore adjacent the ends of the rigid plug, the wire filament from which the spring is formed, is subjected to a relatively higher degree of bending or twisting than occurs at other locations along the length of the spring. The repeated flexing at the same location is believed to result in a work hardening and crystallizing action which renders the stainless steel spring filament subject to corrosion and which eventually leads to breakage of the spring at the particular location.

With the foregoing in mind, the present invention comprises an articulated connector or coupling which, when used to interconnect the ends of the coil springs or spring sections incorporated in the filter media, enables the coupled end portions of the springs to conform more closely than heretofore to the curvature of a roll about which the spring is trained, while minimizing any localized bending or twisting of the spring filament as the spring is flexed in passing'on to and moving from each roll and/or the drum. At the same time, thearticulation of the connector is achieved in such a manner as to subject the latter to minimum wear by abrasive rotary movement of the plugs thereon.

By virtue of the angular movement of the plugs in the axial plane of the pin, the interconnected end portions of the spring adjacent the remote ends of the plugs will be disposed more nearly tangentially to the curvature of the roll around which the coupling passes, than would be the case with a conventional coupling plug as heretofore described, with resulting reduction in the local flexing of the spring coil filament when the coupling passes on to and from a particular roller.

Further it has been found that where the ends of the spring sections are interconnected by conventional threaded plugs, as in the prior art, the relative rotary movement of the spring ends required for threading them on to the plug, will frequently result in torsional stresses in the spring which, at times, may tend to roll it laterally across the discharge roll of the filter. Where tines extending between adjacent spring sections are employed to assist in discharging the filter cake, such lateral displacement of the springs, even though but slight, may result in their damage by the tines.

It has been found that where the plugs are relatively rotatable on their connecting pins to thereby permit free relative rotation of the interconnected spring ends, any such torsional stress or force within the spring is eliminated, together with any lateral rolling tendency of the spring.

It has been found in actual comparative tests, that by use of the connectors of the present invention, the life of the springs constituting the filter media of a filtering unit, is increased by at least several hundred percent over that heretofore obtainable through the use of conventional rigid connectors.

The preferred embodiment of the invention is illustrated in the accompanying drawings in which:

FIG. 1 is a schematic view, partly in elevation and partly in section, through a conventional rotary drum type filter unit employing a filter media composed of coil springs.

FIG. 2 is a greatly enlarged section on the line 2-2 of FIG. 1, showingthe contiguous relationship between the coil springs comprising the filter media in such a conventional filter unit; and

FIG. 3 is a view, partly in elevation and partly in section, on a greatly enlarged scale, showing the preferred form of articulated connector of this invention, operatively applied to one of the coil springs to interconnect adjoining terminal ends of said spring at a location where the spring is curved for passage around one of the supplemental rolls of a filter unit.

In FIG. 1, the reference numeral 2 designates a conventional filter drum disposed for rotation about a horizontal axis 3 with its lower portionimmersed in a vat 4 of sludge to be filtered. Trained around the drum 2 is a flexible porous filter media conjointly defined by a plurality of endless loops 5 of coil springs. As shown in FIG. 2, the coil springs 5, in a preferred configuration, are arranged in inner and outer layers A and B, respectively, with the inner layer A engaging and extending around the drum and spaced apart a distance somewhat less than the spring diameters. The outer layer B of the springs bridges the space between adjoining springs of the inner layer A and is in contiguous engagement therewith to define a composite filter media M extending completely across the drum for its full axial extent, so that a negative pressure maintained within the drum 2, will cause liquid from the slurry within vat 4, to be sucked through the interstices defined between the closely spaced coils of each spring 5 and between adjoining springs, to be received in suitable drainage channels in the filter drum and carried away in known manner, thereby leaving a filter cake deposited on the exterior surface of the filter media M. Both the inner and outer layer A and B of spring coils extend to and over a first discharge roll 6 to maintain the springs 5 in their contiguous parallel status until such time as they reach the discharge roll 6. The springs of the inner layer A then are guided around the discharge roll 6 to and around a return roll 7, and thence back onto the drum 2.

"The outer layer B of springs 5 continues past the discharge roll 6 to a second discharge roll 8 and thence 'to and around a second return roll 9 and back on to the drum 2.

It will thus be manifest that in operation as the lower or inner layer A of the coils diverges from the upper layer B to move around the first discharge roll 6 and thence to the return roll 7, the spring coils 5 thereof are withdrawn or separated from the filter cake which remains on the outer layer B of the springs and is carried thereby to the second discharge roll 8. As the springs pass around the second discharge roll, they are sharply curved and the filter cake, which is normally unable to conform to such a sharp curvature, is discharged for reception on a suitable conveyor not shown. To assist in removing the filter cake as it passes around the discharge roll 8, there may be provided a conventional series of tines, illustrated diagrammatically at T in FIG. 1, which extend between the relatively spaced apart springs 5 of the upper or outer layer B.

It will be readily apparent that in passing around the discharge rolls 6 and 8, all locations along each spring are progressively bent around the periphery of each roll in a given direction of curvature. Then in passing around, their return rolls 7 and 9, respectively, are bent or curved inthe opposite direction. This sharp bending or flexing in opposite directions of each spring is repeated throughout the length of each spring, each time it moves through its endless circuit around the drum 2 and associated rolls.

In order that the coil springs may define endless loops, the opposite ends of each spring 5 are coupled together by a connector which, in the past, has conventionally consisted of a rigid member, often externally threaded, and received within the adjacent ends of the spring. It has been found that when a spring employing such a connector eventually fails, the breakage almost invariably has occurred at or adjacent one of said connectors.

However, where connectors in accordance with the teaching of the present invention are employed, it has been found that in actual practice the life of the springs is increased by several hundred per cent. Moreover, if and when breakage finally occurs, it occurs at a location along the spring remote from the connector or coupling between its ends, thereby indicating that the coupling or connection has a strength and durability equalling or exceeding that of the rest of the spring.

As shown in FIG. 3, the connector of the invention includes a pair of rigid plugs 10-10, respectively, which are formed of a suitable corrosion-resistant rigid material, such as stainless steel. These plugs 10-10 are of identical construction arranged generally in symmetrical aligned relation and proportioned for reception within the ends of a coil spring 5 or springs to be interconnected. The coil spring 5 illustrated fragmentarily in-the drawing is of a conventional construction, being preferably formed of a stainless steel spring wire or filament, wound into contiguous or near contiguous coils 17. It will be understood that a plurality of such coils in parallel contiguous relationship are employed to jointly define a filter media M such as is described in my prior patents aforesaid.

Preferably, the plugs are formed near their relatively adjacent ends with cylindrical portions 12 of appropriate diameter for reception within the end coils of the spring,while the relatively remote end portions 14 of the plugs are formed of relatively reduced diameter, preferably with conical or tapered surfaces which converge away from each other, and which may function as pilots to facilitate insertion of the cylindrical portions 12 into the springs, though the primary function of such tapered portions is to facilitate bending of the springs as hereinafter mentioned.

The plugs 10-10 are interconnected by suitable means permitting universal angular movement between them, so that the interconnected end portions of the spring 15 may bend or flex to substantially the same radius or arc of curvature assumed by the spring on opposite sides of the connector. In addition, it is desirable to permit relative rotary movement between the spring ends, for reasons hereinafter appearing.

Accordingly, in the preferred embodiment, the plugs are formed with normally aligned bores 16 therethrough coaxial to their cylindrical portions 12, and a rigid connecting pin 18 is loosely disposed through these bores with sufficient clearance to permit limited angular movement of the plugs relative to each other and the pin in all axial planes of the pin, as will be apparent by reference to FIG. 3 in which the plugs are shown to be slightly tilted with respect to the pin. Manifestly, the plugs 15-15 are relatively rotatable on the pin 18.

For maintaining the plugs on the pin 18, the latter may be provided with suitable header means in the form of enlargements 20 and 22, respectively, at its opposite ends. In the illustrated embodiment, the pin 18 constitutes a generally conventional rivet having a preformed rounded head 20. It will be understood that the plugs 10-10 are assembled onto the pin 18 together with a conventional retaining washer 24, before the end of the pin 18 opposite its head 20 is upset or riveted over in a conventional manner to define the enlargement 22, the external diameter of which is greater than the internal diameter of the adjacent washer 24,

whereby the entire assembly of plugs and washer is maintained permanentlyon the pin 18.

It will be seen that relatively adjacent ends of the plugs comprise axially presented shoulders or end surfaces 26-26 which, in the preferred embodiment are of annular configuration and extend in radial planes of the respective plugs. These shoulders 26-26 are adapted for axial abutting engagement withradially inwardly directed terminal ends 29 of the wire filament of the coil spring 15. These inwardly directed terminal ends 29 may readily be formed after the plugs are inserted within the adjacent coil spring ends to be interconnected, as by bending the terminal ends of the coil spring radially inwardly by a pair of pliers or other suitable tool.

'In order to maintain a sufficient spacing between the plugs for easy reception of the inwardly directed terminal ends 29, there are interposed between the plugs 10-10 suitable spacer means, here exemplified by annular collars 30-30 formed integrally with the respective plugs, and concentric to the annular shoulders 26 thereof. As'thus formed, the plugs 10 and their associated spacermeans 30 constitute identical unitary structures, thereby achieving economies in boththe production and assembly of the connectors of the invention.

The distance between the enlargements 20 and 22 of the pin '18 is sufficient to permit atleast a limited amount of free axial movement of, the plugs l0so that they may be readily tiltedon the pin 18 without such tilting movement being opposed by abutting relationship between the end faces of their spaces 30-30.

In the use of the invention as a connector for the coil springs of a filter media, as in the earlier identified Komline U.S. Patents, it will be understood that where the opposite ends of the coil spring are interconnected, as in FIG. 3, to form an endless loop which is driven repeatedly through an endless cycle around a filter drum and one or more rollers, the spring will be alternately curved in passing around each drum or rolle-r and then straightened during its passage tothe next roller. in passing around a roller of comparatively small diameter, the spring in its entirety will tend to conform as closely as possible to the uniform curvature of the roller. By virtue of the articulated connector of the present invention, itiis made possible for substantial conformity of curvature to be achieved even atthe coupled end portions of the spring, there being no location along the spring wire filament at which the bending or twisting stresses are concentrated.

Contributing to this is the fact that the axial extent of the cylindrical portion 12 of each plug is relatively small and preferably only somewhat greater than that of a single coil of the spring with which it is associated, and thus, at most can restrain relative axial tilting as between but two adjacent coils, whereas the remainder of the plug 14 istapered or reduced in diameter, and

thus has sufficient radial clearance with the spring that the latter is free to bend or flex in any direction without the coil springs 5, these tines will extend between adjoining springs into near engagement with the roll 8 around which the springs are trained, and in the event any spring has unreleased torsional forces therein tending to cause it to roll laterally on the drum, it may be thereby caused to engage and hang up on one of the tines T, with possibility of resulting damage as by unduly stretching or breaking of the spring.

However, because of the ability of the plugs 12-12 to rotate freely on the pin 18 with respect to each other, and together with the adjacent interconnected ends of the spring, any torsional forces which may be created in the spring incident to interconnection of its ends, will be immediately released through such relative rotary movement at thetime the spring is assembled to the filtering -unit and laterally positioned thereon, thus minimizing any possibility of its damage through encounter with one of the tines T.

An actual embodiment of the connector, as checked out on the test stand, has added phenomenally to the life of the life of the joined spring filament. Data on the performance of this connector and prior art connectors utilizing the articulated connector was determined by the fact that it broke remotely from the joint in the length of the spring rather than at the joint. In other words, we should be able to increase the life of the spring, as applied in practice, most dramatically by more than 3% times.

Further, incidental advantages of the present invention will be readily apparent from the foregoing description and drawings. It is to be understood that in this application I have. shown and described only the preferred embodiment of this invention, and that various changes or modifications may be made therein without departing from the invention as defined in the appended claims.

For instance, it is contemplated that the pin 18 might be formed as an integral portion of one of the plugs, while the bore 16 in such event would be formed only in the remainingplug. The pin and/or bore in such event might be of conical configuration, if necessary, to achieve the desired extent of angular movement between the two plugs.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The combination with a filter unit of the type which includes a coil spring having its ends interconnected to form part of an endless filter media guided for movement in an endless path about a large diameter filter drum and a relatively smaller diameter roller; of an articulated connector for said coil spring ends, comprising a pair of plugs proportioned for reception within the respective said spring ends; said plugs being formed with normally aligned bores therethrough; a

connecting pin extending through said bores and loosely arranged with sufficient clearance to permit angular movement of said plugs in all axial planes of said pin; the adjacent end portions of said plugs respectively being of cylindrical configuration coaxial with said bores and having abrupt axially presented end surfaces directed toward each other at their adjacent ends; said springs respectively having terminal end portions extending radially inwardly between said end surfaces, said terminal end portions being disconnected from said pin whereby said terminal end portions are the means for axially retaining the springs on said plugs; header means on each end of said pin for loosely retaining said plugs on the pin while permitting a limited degree of relative axial movement between the said plugs; and spacer means between said end surfaces comprising integral axial extensions of the respective end surfaces of said plugs and of substantially smaller diameter than said end surfaces and coaxial to said bores.

= 2. The combination of claim 1, wherein the relatively remote ends of said plugs are of reduced cross-sectional area to minimize interference with the ability of the coil spring to bend uniformly throughout its entire length to conform to the curvature of a roll around which the spring is guided for movement. 

1. The combination with a filter unit of the type which includes a coil spring having its ends interconnected to form part of an endless filter media guided for movement in an endless path about a large diameter filter drum and a relatively smaller diameter roller; of an articulated connector for said coil spring ends, comprising a pair of plugs proportioned for reception within the respective said spring ends; said plugs being formed with normally aligned bores therethrough; a connecting pin extending through said bores and loosely arranged with sufficient clearance to permit angular movement of said plugs in all axial planes of said pin; the adjacent end portions of said plugs respectively being of cylindrical configuration coaxial with said bores and having abrupt axially presented end surfaces directed toward each other at their adjacent ends; said springs respectively having terminal end portions extending radially inwardly between said end surfaces, said terminal end portions being disconnected from said pin whereby said terminal end portions are the means for axially retaining the springs on said plugs; header means on each end of said pin for loosely retaining said plugs on the pin while permitting a limited degree of relative axial movement between the said plugs; and spacer means between said end surfaces comprising integral axial extensions of the respective end surfaces of said plugs and of substantially smaller diameter than said end surfaces and coaxial to said bores.
 2. The combination of claim 1, wherein the relatively remote ends of said plugs are of reduced cross-sectional area to minimize interference with the ability of the coil spring to bend uniformly throughout its entire length to conform to the curvature of a roll around which the spring is guided for movement. 